On June 1, the Information Technology and Innovation Foundation held an oxford-style debate over the proposition: "Governments should neither subsidize nor operate broadband networks to compete with commercial ones. Continue reading
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A 3-day wind and solar forecast for Germany from the energy forecaster Enercast:
The forecast allows grid operators to plan ahead for the wind and solar capacity available at a given hour, making it easier to balance load.
A column in the New York Times yesterday suggested that land use is the greatest environmental problem facing new renewable energy. While getting the facts terribly wrong, it opens a door to talk about the advantages of distributed generation such as a unique proposal by Republic Solar Highways to put solar PV on highway right-of-way in California.
Robert Bryce’s column (the Gas is Greener) suggests that wind and solar have a large land footprint compared to gas and nuclear power, and therefore the latter are wiser environmental choices. Of course, Bryce hasn’t read about the Germans, who have installed 10,000 megawatts of solar PV in the past two years, over 80 percent on rooftops. Bryce’s concern for California meeting its 33% renewable energy standard by 2020 (the land use!) crumbles under the German’s torrid pace of rooftop solar development: if the same distributed solar PV program were done in California, the state could meet its RPS five years early without using a single acre of undeveloped land.
Bryce deserves a raspberry for his witless comment about wind farms, as well. Before claiming that wind uses 128 acres per megawatts, he may have wanted to look at an actual wind power project. Over 99 percent of a wind farm is simply the gaps between turbines to prevent interference (“wake turbulence”). In fact, 80 percent of U.S. wind farms use less than an acre per megawatt, one reason that many farmers and ranchers are delighted to host revenue-generating turbines.
Despite its factual foibles, Bryce’s column underscores the fundamental problem with the renewable energy movement. Too many people assume that wind can only be developed in 800 megawatt farms and solar power plants can only be built on hundreds of virgin desert, both linked into high-voltage transmission lines. The Germans put the lie to this assumption with their solar program and wind power development. And innovations in the U.S. also provide compelling counter-examples.
Republic Solar Highways, for example, has proposed a 15 megawatt solar PV project along the right-of-way on U.S. Highway 101 in California. The plan would provide power for 3,000 homes and use land that currently gets an occasional mowing from the Department of Transportation, but is otherwise unused. The idea has a lot of merit, as we explored in our 2010 report Energy Self-Reliant States:
On either side of 4 million miles of roads, the U.S. has approximately 60 million acres (90,000 square miles) of right of way. If 10 percent the right of way could be used, over 2 million MW of roadside solar PV could provide close to 100 percent of the electricity consumption in the country. In California, solar PV on a quarter of the 230,000 acres of right of way could supply 27% of state consumption.
There are environmental drawbacks to some centralized solar and wind projects and their attendant new transmission lines, but Bryce vastly overstates their land use requirements, and glosses over the additional land natural gas and nuclear grind up for mining and extraction. Cost-effective distributed wind and solar power can be built in large numbers without using much undeveloped land, obviating the land use complaint.
P.S. And distributed wind and solar don’t melt down, either.
Photo credit: Flickr user OregonDOT
Mid-May proved beneficial for many high-voltage transmisison developers, as the Federal Energy Regulatory Commission’s “high-voltage gravy train” kept delivering the cash. Five additional transmission projects received incentives, including bonsues to the project’s return on equity or rate recovery during construction. Earlier this year, I wrote about FERC’s program of incentives for new transmission projects, noting… Continue reading
The solution to the variability of wind power is more wind.
The output from a single wind turbine can vary widely over a short period of time, as wind goes from gusty to calm. The adjacent graphic (from this report) illustrates how a single turbine in Texas provided varying power output over a single day, varying from under 20 percent of capacity to near 100 percent!
But the same report also illustrated the smoothing effect when the output from these five wind sites was averaged. The following chart shows (in dark orange), the smoothing effect of output when the wind output was averaged over five sites.
The impact is significant, and the optimized system varies from 15 to 50 percent of capacity, compared to individual turbine variability that’s twice as large. Over a longer period (a year), the optimized (combined) system provides significantly more reliable power to the electric grid. It reduces periods of zero output to a few hours per year, effectively zero probability.
Combining the output of the five sites also increases the probability that the output will be at least 5% or 10% of total capacity of the wind turbines.
Other studies have reinforced these findings. For example, a report by Cristina Archer and Mark Jacobson in 2007 found that dispersing wind at 19 sites over an area the size of Texas increased the level of guaranteed output by 4 times.
Wind power could not be the sole source of electricity for the grid without massive overbuilding of capacity, but its variability is an argument for more dispersed wind, rather than less of it.
An oxford-style debate hosted by the Information Technology Innovation Foundation in Washington DC. Jim Baller and Christopher Mitchell defend local authority to build community networks over the course of a two hour debate. This is an excellent policy discussion. Continue reading
Despite the ample publicity Wal-Mart has engineered for its "buy local" efforts, the company in fact has zero interest in cultivating local suppliers beyond stocking a few token local veggies suitable for a nice photo-op. Continue reading
I just got a copy of a utility bill for a Minnesota business that has a 40 kilowatt (kW) solar PV array. I’d hoped to get a sense for how quickly he’d pay off his array with the net metering revenue. I was shocked. Payback time was 30 years. Even if the business owner had… Continue reading
John Farrell is on leave to spend some quality time with his new daughter. Look back June 6 for more great distributed generation content and an announcement of a new report on distributed generation!
We’ll give you some time insensitive material this week we’ve been saving.
Power plants use a stunning amount of water. In 2005, thermoelectric power (e.g. coal, natural gas) accounted for half of all water use in the United States. Across the country and particularly in the arid West, the water savings from renewable energy are as important as the pollution-free energy.
That makes the distinction in water use between centralized solar and decentralized solar a big deal, especially since centralized solar is only planned for the dry Southwest.
The following graphic illustrates water consumption for common types of power generation per MWh of electricity produced (additional reference here):
Traditional power generators are water hogs. For example, a nuclear power plant consumes 720 gallons of water for each megawatt-hour of electricity produced. Powering a single 75-watt incandescent light bulb for an two hours on nuclear-generated electricity would consume 14 ounces of water (more than a can of pop).
While most of that water is returned to the environment, this report by the Alliance for Water Efficiency and ACEEE notes that it’s not undamaged:
Water is returned to its original source, even though its qualities have changed, especially temperature and pollutant levels.
Nuclear and coal may be big offenders, but wet-cooled concentrating solar power uses even more water per MWh of electricity generated. Dry-cooled CSP cuts water consumption significantly, but it’s still far more than solar power from photovoltaics (or wind power).
If it were solely a question of cost, CSP and PV come out relatively close (see updated chart below) despite the former’s frequent need for transmission access.
But if the tradeoff is significant water consumption versus none, then decentralized PV may make more sense everywhere, including the sunny Southwest.
Photo credit: Flickr user Shovelling Son